Oligomerization process

ABSTRACT

Oligomerization of aliphatic and aromatic monoalkenyl compounds is carried out using elemental iodine as the catalyst and tetrahydrothiophene-1,1-dioxide as the diluent.

United States Patent [1 1 Stapp June 17, 1975 OLIGOMERIZATION PROCESS [56] References Cited 75] Inventor: Paul R. Stapp, Bartlesvi1le, Okla. UNITEDSTATES PATENTS 3,213,155 10/1965 Schriesheim et al 260/683.15 [73] Asslgnee Company 3,488,403 1/1970 Franz 61: al 2601683.]

1 3,723,555 3/1973 Armbrust et'al. 260/668 F [22] Filed: Mar, 15, 1974 3,764,731 10/1973 Armbrust 81 a1. 260/668 j 3,830,863 8/]974 Armbrust et a1. 260/668 F [21] Appl. No.: 451,475 v 1 7 Related U.S. Application Dat Primary Examiner-Paul M. Conghlan, Jr. [63] Continuation-impart of Ser. No. 405,524, Oct. 11,

1973, abandoned. [57] ABSTRACT I 'Oligomerizat ion of aliphatic and aromatic monoalke- 260/668 F; 260/669 P; ggi 'nyl compounds is carried out using elemental iodine as 6 t d t t h h ll d- -d [58] Field ofSearch.... 260/683.1, 683.15 R, 669 P, f j an e m y 6 m e as 6 Claims, No Drawings OLIGOMERIZATION PROCESS This is a continuation-in-part of application Ser. No. 405,524, filed Oct. 11, 1973 now abandoned.

This invention relates to a process for oligomeriza- 5 tion.

Many processes have been developed for the oligomerization of aliphatic and aromatic monoalkenyl compounds. Such processes generally involve high reaction temperatures, high reaction pressures and/or complex catalyst systems. What is desired is an oligomerization process involving mild reaction conditions and a simple catalyst.

It is an object of this invention to provide a novel process for oligomerization.

It is another object of this invention to provide a novel process for the oligomerization of monoalkenyl aliphatic compounds.

It is yet another object of this invention to provide a novel process for the oligomerization of monoalkenyl aromatic compounds.

Other aspects and objects will be apparent to those skilled in the art from the following description and appended claims.

In accordance with this invention, I have discovered that aliphatic and aromatic monoalkenyl compounds can be oligomerized in good yield when contacted with iodine as catalyst in the presence of tetrahydrothiopene-l ,l-dioxide as diluent under oligomerization conditions.

More particularly, according to the present invention there is provided a process for the oligomerization of monoalkenyl compounds selected from the group consisting of:

A. compounds having from 4 to carbon atoms per molecule characterized by the formula wherein each R is independently selected from the group consisting of hydrogen, alkyl, cycloalkyl and aryl; and

B. compounds having from 8 to 20 carbon atoms per molecule characterized by the formula wherein each R is individually selected from the group consisting of hydrogen, alkyl and cycloalkyl; which comprises contacting such monoalkenyl compound with a catalytic amount of elemental iodine in the pres- H CHR R CR3 wherein R is as defined above. Presently preferred are acyclic aliphatic l-olefins having from 4 to 10 carbon atoms per molecule. Examples of olefins useful in the process of this invention include isobutylene, 2-methyl- 2-butene, 3-cyclohexyl-2-pentene, 2,3-dicyclohexyl- 2,5-dimethyl-31hexane, l-phenyl-2-methyl-2-propene, Z-methyl-pentene-l 2-ethylbutene-l and the like, and mixtures thereof.

The oligomer products which can be produced by the oligomerization of olefins in accordance with this invention include dimers, trimers and higher oligomers.

As used herein and in the claims, the terms dimer and trimer refer to compounds formed by the addition reaction of two or three molecules or monomer units, respectively, of a particular oligomerizable monoalkenyl hydrocarbon. The olefin oligomers are unsaturated linear oligomers.

As one example, the oligomerization of a monoalkenyl compound of the formula (A) gives a dimer having the formula together with double bond isomers thereof.

In another embodiment of this invention there is provided a process forthe oligomerization of monoalkenyl aromatic compounds having the general formula wherein R is as defined above. Presently preferred are alpha-alkyl-substituted styrenes having from 1 to 4 carbon atoms in the alpha-alkyl substituent. Examples of alpha-substituted 'sytrenes useful in the process of this invention include alpha-methyl styrene, alpha-ethyl styrene, alpha-propyl styrene, alpha-butyl styrene, pethyl-alpha-methyl styrene, and the like, and mixtures thereof.

The oligomer products which can be produced by the v oligomerization of alpha-substituted styrenes in accordance with this invention include cyclic dimers having the general formula wherein R is as defined hereinbefore.

The process generally comprises contacting the reactant hydrocarbon with a catalytic amount of elemental iodine in the presence of tetrahydrothiophene-l,ldioxide. Iodine is employed in approximate amounts ranging from 0.01 to 1 part by weight per one hundred parts by weight of reactant. Tetrahydrothiophene-l ,ldioxide is employed as diluent in an approximate diluentzreactant weight ratio ranging from 5:1 to 1:5.

Process conditions will vary according to the particular reactant employed. In general, the process is conducted under conditions of temperature, pressure and time sufficient to effect the desired degree of reaction.

The temperature of the reaction determines to a substantial extent the range of hydrocarbons which will occur in the product. An increase in temperature generally increases the yield of higher oligomers. Reaction temperatures can range from about 25 to about 250C. Temperatures within the range of 100 to 200C. are presently preferred. 9

Reaction pressure can range from atmospheric up to about 5000 psig. When the process is conducted in a pressure vessel, such as an autoclave, reaction pressure can be autogenous although in some instances it may be desirable to pressurize the reactor with an inert diluent gas.

The time of reaction is determined by the desired degree of reaction, reactivity of the reactant and the temperature employed. The time of reaction can range from about 10 minutes to about 10 hours.

Following completion of the reaction period, the products can be separated from the reaction mixture using any convenient method such as decantation, fractionation, and the like. The diluent, catalyst, and unconverted feedstock can be recycled, if desired.

The oligomers produced in accordance with this invention can be used for many purposes well known in the art, for example, as chemical intermediates, as plasticizers, as comonomers in addition polymerizations and as lube oil additives.

The following examples illustrate this invention.

EXAMPLE I To a l-liter autoclave were charged 250 grams of tetrahydrothiophene-l,l-dioxide, 0.5 gram of iodine and isobutylene, in amounts shown below. The reaction mixtures were heated to 200C. for 2 hours at autogenous pressure. At the end of 2 hours, the reaction vessel was cooled. 'Unreacted isobutylene, if any, was vented into an acetone-dry ice trap where it was recovered. The reaction mixture consisted of an upper hydrocarbon layer and a lower tetrahydrothiophene-l,ldioxide layer.

lsobutylene conversion and yields of the dimer and trimer were determined by gas-liquid chromatographic (GLC) analysis of the two liquid layers. Identification of the components was made by comparison of GLC retention times to those of known compounds. The data are uncorrected; analysis was made by direct comparison of the areas under the curves without application of a sensitivity factor or an internal standard.

Results of two runs are given in Table I. The values for conversion and yield are based upon the amount of isobutylene consumed in the reaction.

TABLE I lsobutylene Charged, onversion, Yield Yield Run Cirarns Dime r,%" Trimer,%

""Approximate thermodynamic distribution of isomers: percent 2,4.4-trimethyll-pcntenc; 20 percent 2.4,4-trimethylZ pentene.

""Three of the possible isomers were observed by GLC. The structures were not determined.

This example illustrates that dimers and trimers are produced in good conversion and yield according to the process of this invention.

EXAMPLE II Two runs were conducted using the procedure of Example I with variations in reaction temperature. Results of these runs are given in Table II.

TABLE II lsobutylene Charged, Temp. Conver- Yield Yield Run Grams C. sion, Dimer,%" Trimer,%

""Approximate thermodynamic distribution of isomers: 80 percent 2,4,4-trimethyl-l-pentene; 20 percent 2,4,4-trimethyl-2-pentenc. 'Three of the possible isomers were observed by GLC. The structures were not determined.

This example illustrates that lower temperatures, as compared to Example 1, promote formation of the dimers.

EXAMPLE III For purposes of comparison, two runs were conducted using the general procedure of Example I, using Lewis acids as catalysts in place of iodine. One gram of catalyst was used. The reaction mixtures were heated to C. for 2 hours. Results of these runs are shown in Table III.

TABLE III lsobutyl- Cataene Chgd. Conver- Yield Yield Run lyst Grams sion, Dimer,%"" Trimer,%

5 AlCl; 302 0 trace 6 ZnCl 315 23.7 38

""Approximate thermodynamic distribution of isomers: 80 percent 2,4,4-trimethyl l-pentene; 20 percent 2,4.4-trimethyl-2-pentene. "Not determined.

EXAMPLE IV EXAMPLE V Two runs were conducted essentially as described in Example I using propylene in place of isobutylene at temperatures of 125 and 200C. for 3 hours. No reaction occurred to any appreciable extent in either run.

EXAMPLE VI To a 1-liter round bottom flash equipped with magnetic stirrer, thermometer, and reflux condenser were charged 250 ml of tetrahydrothiophene-l,l-dioxide, 1.0 gram of iodine and 227 grams of alphamethylstyrene. The mixture was stirred, under nitrogen, at a temperature of 150C. for 2.5 hours. The reaction mixture was cooled, then diluted with 500 ml of water and extracted with ether. The combined ether extracts were washed successively with water, sodium bisulfite solution and water, then dried over anhydrous magnesium sulfate and filtered. The ether was removed by distillation at atmospheric pressure. Distillation of the residue at reduced pressure gave 163.1 grams of product identified by nmr, mass spectrometry, and IR spectrometry as 1,3,3-trimethy1-l-phenylindane. Yield 71.9%.

Reasonable variations and modifications of this invention will be apparent to those skilled in the art in view of this disclosure. Such variations and modifications are within the scope and spirit of the disclosure.

What is claimed is:

l. A process for the oligomerization of a monoalkenyl compound selected from the group consisting of A. compounds having from 4 to carbon atoms per molecule characterized by the formula wherein each R is independently selected from the group consisting of hydrogen, alkyl, cycloalkyl and aryl; and

B. compounds having from 8 to 20 carbon atoms per molecule characterized by the formula wherein each R is independently selected from the group consisting of hydrogen, alkyl and cycloalkyl; which comprises contacting said monoalkenyl compound with a catalytic amount of elemental iodine in the presence of tetrahydrothiophene-l ,l-dioxide as diluent under oligomerization conditions wherein said tetrahydrothiophene-l,l-dioxide is present in an approximate weight ratio of diluent to monoalkenyl compound ranging from 5:1 to 1:5, and the process temperature is in the approximate range of 25 to 250C.

2. The process of claim 1 wherein said iodine is present in an approximate amount ranging from 0.01 to 1 part by weight per parts by weight of said monoalkenyl compound.

3. The process of claim 2 wherein said monoalkenyl compound is an acyclic aliphatic l-olefin having from 4 to 10 carbon atoms.

4. The process of claim 3 wherein said olefin is isobutylene.

5. The process of claim 2 wherein said monoalkenyl compound is an alpha-alkyl-substituted styrene having from 9 to 12 carbon atoms.

6. The process of claim 5 wherein said substituted styrene is alpha-methylstyrene. 

1. A PROCESS FOR THE OLIGOMERIZATION OF A MONOALKENYL COMPOUND SELECTED FROM THE FROUP CONSISTING OF A. COMPOUNDS HAVING FROM 4 TO 20 CARBON ATOMS PER MOLECULE CHARACTERIZED BY THE FORMULA
 2. The process of claim 1 wherein said iodine is present in an approximate amount ranging from 0.01 to 1 part by weight per 100 parts by weight of said monoalkenyl compound.
 3. The process of claim 2 wherein said monoalkenyl compound is an acyclic aliphatic 1-olefin having from 4 to 10 carbon atoms.
 4. The process of claim 3 wherein said olefin is isobutylene.
 5. The process of claim 2 wherein said monoalkenyl compound is an alpha-alkyl-substituted styrene having from 9 to 12 carbon atoms.
 6. The process of claim 5 wherein said substituted styrene is alpha-methylstyrene. 